The present invention relates to a drive for four-wheel driven motor vehicles such as lorries, buses and tractors.
In four-wheel drives for lorries, buses or tractors having six or more wheels it has so far been usual to equip the four driven wheels with separate driving axles, the connection between the driving axles and the change speed transmission being effected via universal-joint shafts. This solution presents the disadvantage that the universal-joint shafts have to transmit very high torques in the low gear. In vehicles driven by turbines there arises the additional disadvantage that the overall speed transformation must be effected substantially in the transmission range so that an input or an output transmission must be arranged at the input or output of the change speed transmission. Until today the vehicles were mainly equipped with friction clutches for starting operation which have to be actuated by hand, in heavy cars hydraulically or pneumatically by means of jaw means.
In order to relieve the driver especially in fast running lorries or omnibuses there is the demand to facilitate the manual operation. The provision of hydrodynamic torque converters would meet this demand, but converters show the known disadvantages in causing a 8 to 10 % loss of power. Another proposal was to provide the transmission with brake means located within the oil filled transmission box. But this arangement causes increased heat dissipation and affords the provision of large filter means. The present invention eliminates the disadvantages arising in connection with the used drive constructions and the use of starting clutches.
Accordingly it is the main object of this invention to provide a new drive for four-wheel driven vehicles employing a new drive unit.
It is further an object of this invention to provide a new compact mounting of the substantial parts of this drive unit so that a common housing enclosing all drive unit parts may be provided.
It is further an object of this invention to provide a suspension of the drive unit on the chassis frame.
A further object of this invention is to equip the drive with a new starting device replacing the starting clutch usually provided between the engine and the drive input, the starting device employing a watercooled brake.